The objective of this project is to examine the role of cellular immunity in periodontal disease. In particular, the molecular events related to plaque-mediated lymphocyte activation and its control by regulatory molecules e.g. cyclic nucleotides, prostaglandins, lymphokines, serum activators or inhibitors will be studied in specifically designed cell-culture systems derived from mice and humans. Molecules of specific interest (lymphokines etc.) will be purified and studied in an effort to define their mechanism of action. Particular emphasis will be placed on a study of the lymphokine, osteoclast activating factor (OAF) in the pathophysiology of periodontal disease as well as other bone diseases. Additionally, the role of "growth proliferative" cyclic GMP dependent enzymes will be investigated in both normal and abherent cellular proliferative processes e.g. neoplasia and leukoplakia. From the knowledge gained in these studies, specific therapies against oral disease will be designed.